1. Field of the Invention
The present invention is directed towards a bone anchor, an anchor-insertion tool, and a surgical kit employing the same. These apparatus are particularly suited for a laparoscopic urethropexy procedure for the correction of female stress urinary incontinence. More particularly, the present invention provides apparatus for performing the urethropexy through laparoscopic techniques, thereby greatly reducing the duration, discomfort, and recovery period of such surgeries.
2. Description of Related Art
Female stress urinary incontinence (SUI), defined as the unintentional loss of urine, can be a socially unacceptable problem for many women. Most often, the incontinence occurs during coughing, sneezing, or physical activity in women afflicted with this problem. While effective surgical treatment for this condition has existed for nearly 50 years, the procedures typically involve major abdominal surgery with accompanying post-operative limitations lasting six to eight weeks. Because of the nature of these surgical procedures, many women simply resort to diaper-like incontinence pads, or simply avoid any activities which result in the unintentional loss of urine.
In the normal resting state, the external pressure exerted on the collapsible urethra by the surrounding musculature is greater than the pressure exerted on the bladder, and therefore continence is maintained. During moments of coughing, sneezing, or physical activities, greater pressure will be exerted on the dome of a filled bladder. In women not afflicted with stress incontinence, a corresponding increase in the external pressure on the urethra acts to prevent the unwanted loss of urine from the bladder. Sufferers of SUI, however, aren't so fortunate.
Stress incontinence is generally caused by two etiologies: a spastic detrusor muscle; or a loss of support of the periurethral tissue at the urethra-vesicular junction ("UVJ"--the region where the urethra enters the bladder). When the latter situation occurs, the UVJ will sag into the vagina, thereby reducing the pressure which can be exerted on the urethra during moments of stress. Diagnosis of any sagging of the UVJ can be easily determined by inserting the tip of a cotton swab into the urethra until it reaches the UVJ. The patient is then asked to bear down as if urinating, and loss of the UVJ support is readily identified by the upward movement of the wooden end of the cotton swab. In this test, the external urethral meatus acts as a fulcrum for the tip of the swab, and the elevation of the opposite end indicates the downward descent of the UVJ. U.S. Pat. No. 4,072,144 provides an alternative device which may be utilized to readily measure the angle of the UVJ in a similar manner.
The first urethropexy procedure for eliminating SUI caused by a sagging urethra was developed in 1948 by Drs. Marshall, Marchetti, and Krantz, and generally involves the fixation of the periurethral tissue at the UVJ on either side of the urethra (MMK procedure). Fixation in the MMK procedure, also known as urethropexy or abdominal culposuspension, is accomplished by suturing the periurethral fascia at the UVJ on either side of the urethra to the periosteum of the pubic bone. The procedure essentially alters the angular relationship between the urethra and bladder by elevating the UVJ, and therefore preventing the sagging of the UVJ when downward pressure is applied to the region by various stresses.
The MMK procedure has been perfected over the years, however the essential principles have remained the same. In 1955 Burch developed the technique of affixing the periurethral fascia bilaterally to Cooper's ligament, thereby resulting in a technically easier procedure because of the previous difficulties in passing a needle through the periosteum of the pubic bone. Although the Burch procedure has been performed laparoscopically, the five-year failure rate for the open Burch procedure is approximately 60%. A laparoscopic Burch procedure is even more problematic since it is extremely difficult and time-consuming to tie sutures laparoscopically.
Alternatively, urological procedures such as that of Stamey, Raz and Peyerra have been developed, however these are typically blind procedures which require the passing of long needles through the rectus fascia to the periurethral fascia utilizing a cystoscope. Although these urological procedures avoid the 10-centimeter midline or Pfannenstiel incision and its required three-day or longer hospital stay, the gynecological procedures of MMK, Burch and others have proven to be the most effective. In fact, the scarring of the urethra and interior bladder as well as the scarring of the periurethral tissues, aids in fixation of all of the involved tissues during the MMK and Burch procedures, thereby assisting in the prevention of incontinence.
Recently, a modified version of the MMK procedure has been developed which utilizes bone anchors secured directly to the pubic bone on either side of the symphysis for fixation of the UVJ. The apparatus for performing this modified MMK procedure are sold by Mitek Surgical Products, Inc. of Norwood, Mass., and a number of U.S. patents concern these products (see, e.g., U.S. Pat. Nos. 5,207,679, 5,217,486 and 4,899,743). In the Mitek-MMK procedure, a Pfannenstiel incision must be made in the abdomen in order to provide access to the space of Retzius. The space of Retzius is in actuality a "potential" space in that it contains various connective tissues and fats which must be dissected in order to provide sufficient access to this region. In fact, this connective tissue, particularly the areolar adventitial tissue, generally breaks down after delivery of a child, and this breaking down of the connective tissue often contributes to the onset of SUI in many women.
Once the space of Retzius has been dissected in the Mitek-MMK procedure, small anchors are secured in the pubic bone on either side of the pubic symphysis. Each of the bone anchors has a suture attached thereto, and these sutures are threaded through the periurethral tissue on either side of the urethra. The sutures are then tied off in the abdomen so that the periurethral tissue is pulled upward, which in turn restores the angle of the urethra at the UVJ, thereby restoring the urethra to its proper location. While the Mitek-MMK procedure is highly effective, it is a lengthy and complicated procedure which can generally only be performed by highly-skilled surgeons.
The present invention offers an unique anchor design for use in a laparoscopic urethropexy procedure, as well as an inserter for placing the anchor within a bore created in the patient. These apparatus are particularly suited for laparoscopic urethropexy, however the use of the devices is not so limited.